code: def build_roi_extractor(cfg):
      """Build roi extractor."""
      return build(cfg, ROI_EXTRACTORS)
  
file_path: insightface/detection/scrfd/mmdet/models/builder.py
imports: from mmcv.utils import Registry, build_from_cfg
  from torch import nn
label_desc: Use image node_id 4 for calling a global function with example usage: build_roi_extractor(cfg) and returns: build